so you are going to use the Pythagorean theorem on the smaller triangle to find the connecting side's length
[tex] {5}^{2} = {3}^{2} ( {b}^{2} ) \\ b = 4[/tex]
now you can find the bigger triangle's hypotenuse
[tex] {6}^{2} + {4}^{2} = {c}^{2} \\ [/tex]
c=4
